Land mine



April w, 1946. a MET'CALFE. 2,399,242"

LAND MINE Filed on 15, 1942 El amuel L- Matcalfe Patented Apr. 30, 1946UNITED s'r'res (Granted under the act of March 3, 1883, as amended April30, 1928; 370 0. G. 757) 1 Claim.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

This invention relates to a land mine, and in particular, one that isadapted to damage the tread of a tank or the wheel of a truck orairplane, the size and weight to be as small as consistent with suchtactical uses. Such a mine would be filled with explosives stable enoughto withstand dropping from a great height yet sensitive enough todetonate upon pressure from the tread of a light tank.

Briefly, these and other objects are attained by employment of a minedivided into three compartments, one containing a stable explosive andthe other two compartments containing substances in a liquid or gaseousform which upon being mixed form an explosive of sufficientsensitiveness to explode upon light pressure and with sufi'lcient powerto set off the main explosive.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawing in which:

Fig. 1 is a sectional view taken on the line l-l of Fig. 2.

Fig. 2 is an end view of the mine, and

Fig. 3 is a side view of a modified mine.

Referring to the drawing by characters of reference there is shown amine with a main outer casing I, made in two sections, and having afiller cap 2 for the opening through which a main explosive 3, such asTNT is charged into a chamber defined by a partition 4. A furtherpartition 5 of more solid construction than partition 4 further dividesthe mine into a chamber for reception of sensitizing components which inthe preferred example shown comprises carbide 6 in one compartment andwater I in the other.

A stopper mechanism is preferably employed to normally separate thesensitizing components and permit mixing thereof at the proper time.Thus, a stopper seat is provided in the wall 5 to receive a stopper 8.The stopper seat will preferably be supplied with a gasket 9 to providea water-tight seal. A stopper assembly plug I is threadedly received inthe casing I against a gasket II and has a central bore [2 to receivethe stopper stem l3. A boss I 4 is provided on the plug l0 and both theboss 14 and the stopper stem l3 are drilled to receive a pull pin l anda shear pin 16. The valve 8 is thus seated tightly against its gasket 9by continued turning of the plug In, the

Pull pin l5 imparting the turning movement to the stopper stem. Packingl! is provided between the plug and stopper stem and a filling plug itis provided in the plug.

Operation-Prior to dropping the bomb the pull pin I5 is removed and thisleaves the stopper supported against its gasket pressure only by theshear pin 56. Upon impact with the ground the bomb tends to be deformedwith a consequent lessening of volume and the stopper 8 is forced awayfrom its seat, shearing the shear pin l6 either wholly or in part. Ineither case the water seal is broken and the water seeps into thecarbide and generates acetylene gas. This forces the stopper stemoutward until the underside of the stopper seats against the plug it,and thereafter pressure builds up in the now combined chambers 6 and l.Acetylene itself is not explosive under ordinary conditions, but becomesso when subjected' to high pressure, breaking up into carbon andhydrogen with the evolution of heat, and this heat speeds up the furtherdecomposition, and no auxiliary oxygen supply is necessary for theexplosion since mixtures of acetylene and air are explosive throughout awide range of percentage composition and mixtures with as loW as 3% ofair by volume will explode at about 500. Thus the residual air in theinterstices of the carbide will suffice. The pressure required isfurnished by the confinement of the gas being generated together withthe heavy tank or other vehicle which, in passing over, deforms the mineand thus creates further pressure. The violence of the acetyleneexplosion is sufficient to detonate the main charge. The amount ofacetylene and volume of the chambers will be so adjusted thatspontaneous detonation of the gas under its own pressure Will not takeplace.

The mine will preferably have a curved outer casing to better withstandthe shock of impact when dropped. The mine may be truly spheroid asshown in Figs. 1 and 2, but any rounded contour will sufiice. Inparticular, it may have a flattened portion 19 as shown in Fig. 3 toprevent rollin and thus improve the accuracy of placement as well asrendering it more tractable when engaged by a vehicle. It will befurther noted that if impact occurs in a region behind the stopper, thepin will still be sheared though in a sense opposite to that whichoccurs when the stopper is forced outwardly of its seat. The resilienceof the gasket under the stopper will then force it back sufficiently topermit entry of the water.

The smallest seepage will suflice. In most cases of impact the inertiaof the stopper alone will be a large contributing factor to the shearingof the pin.

I claim:

A land mine comprising an outer casing deformable upon impact, aplurality of partitions dividing the mine into compartments, a highexplosive in one compartment, carbide in another of said compartments,water in the compartment adjoining the carbide containing compartment, aplug in the water compartment and having a porin the partition betweenthe water and carbide compartments, a movable stopper spaced from theplug and normally closing said aperture and having a guiding stemextending through the plug, said stopper being adapted to be forced fromits seat upon the deformation of the casing to establish initialcommunication between the carbide and water compartments, and be furtherremoved from its seat upon generation of pressure in the carbidecompartment to establish full com- 10 munication between saidcompartments. tion extending outside of the casing, an aperture 7 SAMUELL. METCALFE.

